Typical electrophotographic (EP) devices have a spinning polygon mirror for directing a laser beam on a photoconductor, such as a drum, to create one or more scan lines of a latent to-be-printed image. With reference to FIG. 1, multiple scan lines (1-6) are shown and all extend in the direction of the arrows left-to-right in the scanning direction 10. Conveniently, common referencing of all scan lines can occur relative to a single laser beam sensor position 12, known commonly as a horizontal synchronization (or “hsync”) position. Often, the hsync signal is defined in units of time for the engine of the EP device and its apparent location exists in a space somewhere off the edge of the printed page.
Recently, it has been suggested that torsion oscillator or resonant galvanometer structures can replace the traditional spinning polygon mirror as the means for generating scan lines on the photoconductor. In this manner, scan lines occur in both the forward and backward directions (e.g., bi-directionally) thereby increasing efficiency of the EP device. Due to their small size and less involved fabrication techniques, the structures are also fairly suggested to reduce the relative cost of manufacturing. However, scanning in two directions adds complexity to image referencing since two reference points need occur at opposite ends of the printed page and even the slightest of deviations between scan lines amplifies print image imperfections. Moreover, scanning is influenced by temperature, which thus affects the magnitude of the scan line misalignment.
Accordingly, there exists a need in the art for adjusting for the manner in which bi-directionally scanning EP devices should operate according to temperature. Particularly, there are needs by which knowing the actual operating temperature of the EP device will relate to making corrections to improve print quality. Ultimately, the need extends to accurately aligning and registering the pixel information of the forward and reverse bi-directional scan lines. Naturally, any improvements should further contemplate good engineering practices, such as relative inexpensiveness, stability, low complexity, ease of implementation, etc.